750 Roadster Exhaust Silencers

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Thanks Joe, I was hoping you would respond. No one in the past I think has believed me. The other bike I referred to has the same baffle, it's a Nov '69 production bike with what look like original S type peashooters. I'm going to drop a light in the front end of mine this morning and see if I can get a picture of the flutes, which look more like gills.

Here's the other 'S' exhaust from the rear showing the baffle.

750 Roadster Exhaust Silencers


Dave
 
I've got some pictures of the flutes and a bit more understanding of what's inside. I hate to cut it up to really see. Maybe Joe can clear it up. Anyhow, look at the drawing, it explains it more than words could. I don't know how things are attached at the baffle end though. This is what it appears to be like.

750 Roadster Exhaust Silencers


And here's a couple pics of the flutes.

750 Roadster Exhaust Silencers


750 Roadster Exhaust Silencers


I wonder if these couldn't be made up somehow, I remember ludwig said he made his own silencers from SS.

Dave
 
That's some good light and camera aiming to get a view of the insides. Note the finger nail clipping size-shape flutes straight thru. I don't think we want a big size baffle in the flow even if it 'twitters' or 'tweeters' on let offs.

In summer of '99 on The 6th day of my 1st factory Combat I was invited to ride over night with a bunch of locals mostly on Harely's and they said they could tell it was me on a Norton from miles away as throttled up some but mostly off as I descended on trailing throttle down into town. One of the bunch was famous for his '71 he literally lived on so recognized the sound signature. 7th day Turned out the camp site was a real drag strip so while the racers were doing early am cool temperature time trials I got inspired to try launches on the hwy to point of small wheelies till one of the rusted neck silencers fell off so took off the other rusted one which really woke up the upper power band on open headers, which inspired me to barrow a helmet and get some X-mass tree adrenalin thrills. That was the end of those tweetie pie's.

A few year later a UK member of Brit Iron list and NOC/UK forum got to into investigating why the missing twiiter to finally snag an early 70's peashooter that did to find apparently it was the size shape and direction and lenght of the flutes section only as the views he posted showed straight through pipe. My main 'puter is dead so no email to BI list for a while but will ask them if they remember and can pull up the archive on it. If a full smooth tapper non step up neck reverse cone with a twiiter sound became available they'd likely sell like hot cakes.
 
A little more discovery. Here's a better pic of the baffle. It appears that the larger inner tube is blocked maybe 80% by the baffle at the end and there is a tab that holds the baffle at the end of the tube and also holds the end of the tube in the outer shell.

750 Roadster Exhaust Silencers


750 Roadster Exhaust Silencers


Actually the baffle is about an inch in front of the widest point of the peashooter.

I'm tempted to put these on my bike and see what they sound like compared to the Wassal ones.

Dave
 
The other one has 2 holes. Maybe it tweets twice as fast. Or it's to let the water out.
 
Looking at the drawing for 06-1312 again, and only after seeing your pictures, the difference in silencing technique becomes obvious.

The internal diameter of the fluted tube on the later silencers continues the diameter of the inlet pipe, whilst on the early 06-1312 "S"-type silencers the fluted tube goes up in diameter, then has the baffle piece in the end. Which, by the way, is a triangular thing on the drawing whilst your looks like a round piece put in with a bracket.
 
This thread is degenerating.

Yeah, Joe, the pipe goes from the nominal 1 1/4" id at the input and steps up at 10", but I can't tell if the larger fluted tube is tapered or not, I think maybe it is. It's about 2 1/2" at the end of the fluted pipe.

If I get the motivation up this autumn, I'll do a video demo of both the straight through fluted silencer vs. the 06.1312 S type. I certainly don't remember any whistling, trilling or tweeting on my originals. I just though they sounded better, but it may be 'selective memory' too.

Joe, so the Roadster/ silencers (06.1608 for the 70 USA Roadster and FB) were made different inside than the S type? I think the early FB and R(?) had the 23767/8 cigar type silencers.

Dave
 
Dave,

The 06-1608 (drawing dated 17th December, 1969) were internally similar to the original 06-1312, but the rear end was different. They had a labyrinth arrangement at the end. They were superceded by the 06-1978, i.e. the last Roadster silencer internal design, which is what we produce today and the internals of which we use on our 06-1312.

Early Fastbacks and "R" models used the Dominator silencers, even the part numbers remained the same.

Joe/Andover Norton
 
The new production :D AN Roadster silencers are very nice

I actually got lucky with a pair I ordered replacements from a Uk Wholesaler when they arrived they were embossed with the Norton logo ( Genuine )
It looks like Brituro make the Genuine embossed AN silencers but are not fussy who they sell them to
 
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